Previous studies of hypertrophic scars and keloids suggested a possible hyperactive immune system, accumulation of plasma proteins, an latered microvasculature and a chronic hypoxic state as associated and integrated factors of their etiology. These possible events will be evaluated by studying abnormal scars for several immunological biochemical and morphological characteristics, including electron microscopy. Studies will be extended to the biochemistry of normal skin, scar or keloid tissue and granuloma tissue of implanted PVA sponges. Samples of tissue will be analyzed by morphological, biochemical and immunological methods (DNA, fibroblast count using antifibroblast serum, prolyl hydroxylase, collagenase, rate of collagen biosynthesis, types of collagen, total amount and fractions of collagen tissue antigens). In animal studies rabbits will be immunized with collagen in Freund's adjuvant. Incision and excision skin wounds will be inflicted in several regions, sponges implanted s.c. and the kinetics of healing -related to various aspects of collagen chemistry will be studied. Cultured fibroblasts from keloid tissue will be assayed for surface antigen and compared with values attained on an equivalent basis with WI-38 cells. The aim of this research is to provide more definitive information as to the true etiology of keloids and hypertrophic scars. These lesions are peculiar to man and it is hoped that with new information, their eventual control of development would be at hand.